Signal control circuits



Nov. 30, 1937. T. u. WHITE SIGNAL CONTROL C RCUITS Filed OCb. 10, 1932 3SheecS-Sheeb l Nov. 30, 1937. 'r u. WHITE SIGNAI CONTROL cRcUITs Filed001;. 10, 1932 3 SheebS-Sheet 2 rrr.

Nov. 30, 1937. T. u. WHITE SIGNAL CONTROL CIRCUITS Filed oct* lO, 1932 3Sheets-Sheet 3 Patented Nov. 30, 1937 PATENT OFFICE SIGNAL CONTROLCIRCUITS Thomas U. White, Chicago, Ill., assignor to Associated ElectricLaboratories, Inc., Chicago,

Ill., a corporation of Delaware Application October 10, 1932, Serial No.636,984

6 Claims.

The present invention relates in general to signal control circuits, butis particularly concerned with the provision of circuits and apparatusfor protecting equipment of a low voltage signalling system in which thesignalling circuits are of such a character as to require the frequentinterruption of such circuits. Such circuits often include a number ofmultiple paths and carry a load which is great enough to produceexcessive arcing at contact springs, employed frequently to interruptpoints in the circuit which are common to they combined load of a numberor all multiples of the circuit. In such circuit arrangements lamps aresometimes lighted over conductors extending a substantial distance fromthe source of current employed, causing a quite noticeable voltage drop.Certain of the protecting equipment of the present invention inherently,to a certain extent, overcomes this undesirable feature, incidental toits use for protecting purposes, but which may also be employed atstrategic locations to assure uniform brilliancy of all the lamps of thesystem. In a chain circuit including a great number of switchingcontacts serving as a common feed conductor for a large number of lamps,sectionalizing relays are used to break up the chain circuit intosmaller sections. The application of potential to one end of a sectioncauses a relay at the other end of the section to apply potential to theadjacent section, and so on. With this arrangement small Wire can beused onY each section because of the smaller number of lamps in eachsection reducing the amperes in such sections. In addition, auxiliarycircuits are established for the lamps while the switching contacts inthe series circuit are being opened. These auxiliary circuits also shuntthe switching contacts to temporarily carry the load so as to preventinjurious arcing at 40 the operated contacts during their operation.

An object of the present invention is to provide sectionalizing meansfor such circuits to limit the loads carried by them., thus in eiiectenabling an unlimited number of multiple oircuits to be controlled asone.

Another object is to provide sectionalizing means which will function toapply potential from either section to the other,

Another object is to provide a line sectionalizing equipment which maybe employed in line loops without danger of the equipment beingimproperly locked up over such loops.

Another object is to provide circuit sectionalizing means which may alsobe employed as a current booster.

(Cl. 177-3l1) A further object is to provide load shunting circuits andapparatus which permits the safe and satisfactory use of contacts forcontrolling circuit loads which would not otherwise be satisfactory forthe control of such loads.

The invention has been shown and described as a part of the circuits andapparatus of a` power supervisory board. Fig. 1 of the drawingsconstitutes a map representing the apparatus and interconnections of apower net-work. This map may be built along the lines of the map shownin the co-pending White Patent No. 2,010,338, granted August 6, 1935.Fig. 2 diagrammatically illustrates the selecting equipment employed bythe power supervisor in controlling the display signals and the symbolsof the map shown in Fig. 1. Fig. 3, which should be placed to the rightof Fig. 2, diagrammatically illustrates the circuits and apparatusdirectly and indirectly controlled by the supervisor to maintain thedisplay condition of the map, shown in Fig. l, in a display conditionrepresenting the condition of the actual equipment represented or aproposed change in the condition of the actual equipment.

Referring now particularly to Fig. 1, the manner of reading the map willbe briey explained. In the network illustrated in this figure, thesource of current normally supplying the network is supplied from agenerator, which, when active, is represented by the lighted conditionof the symbol labeled Gen tell-tale which is lighted by the lampssimilarly labeled in Fig. 3. In an emergency, current from anothernetwork may be supplied to the present network at the point labeledInterconnection. The various tell-tale symbols representing buses,lines, and transformer banks, have been labeled and can therefore bereadily identified. These tell-tale symbols are provided with lamps,which, with their controlling circuits, are shown in Fig. 3. In Fig. lone each of the bus disconnect, line disconnect, by-path, and oilswitches have been appropriately labeled so that any of such switchesmay be readily identified.

These various switch symbols are equipped with mechanical indicators ofthe type disclosed in the copending Obergfell Patent No. 1,966,042,granted July 10, 1934. Two of these indicators, 20B and 260, arediagrammatically shown in Fig. 2. The contacts on these indicators, aswell as those not shown in Fig. 2, are shown in Fig. 3, and by theirclosed or open condition control the various tell-tale circuits at thesame time that ,their semaphore cylinder causes their associated symboltoindicate to the supervisor the open or closed condition of theapparatus represented.

The equipment shown in Fig. 2 comprises a Strowger switch SS of thewellV known vertical and rotary type, which responds to dial impulses torst select one of ten groups of contacts and which is then rotated toselect a desired Contact of such group. VOnly two mechanical indicatorsare shown connected to the bank of the switch shown in Fig. 2, but itshould be understood that w there is actually one of these devices foreach of the switches represented in Fig. 1 and that each of thesedevices is equipped with contacts as shown in Fig. 3. The supervisorexercises full control over the selectionand operation of the Ymechanical indicators, such as 260 and 200, by the use of the callingdevice CD', and keys KV and KI, respectively. In the operation, the keyKlis rst operated followed by the operationof the calling device toappropriately position wiper 2 l0 of switch SS,-after which the key K isoperated enabling the subsequent operation of the calling device tooperate the selected indicator, as will'be subsequently more fullyexplained.

As previously mentioned, the equipment of Fig. 3 includes the tell-talecircuits and lamps used to light up certain symbols of the map shown inFig.

' land the tell-tale circuit controlling contacts of the mechanicalindicators employed in conjunction with the symbols representing theswitching devices. `VThis gure, in addition, includes protectiveequipment including a pair of load shuntingY relays 30| and 302 which,through the medium of their contacts, provide individual circuits forthe various tell-tale lamps of the board and which serve to carry theload required to light these lamps, while circuits, normally including aplurality of the indicator contacts in series, ordinarily carrying theload of these-lamps are being opened and closed by the supervisor. Theload shuntingrelays are Valso employed to cause any lampotherwise'deprived of current to intermittently ash-so that theassociated symbol will signify-to the power supervisor the loss oicurrent at such point in the system. Fig. 3 also contains a pair of linesectionalizing relays 303 and 304 employed to break up a long line intosections so as to limit the line load, thus enabling the use ofrelatively small line wires, which are much more readily employed inmaking the required connections to indicator and relay contacts. VInarranging the. circuits Vin this manner long lines are avoided and therelays 303 and 304 therefore serve as boosters maintaining an evenbrilliancyY of the lamps of all line sections even when distributed overaV comparatively large area Von theV board.

' Itwill be. noted from an inspection of Fig. 3 that the contacts 300ofthe mechanical indicator,associatedwiththe oil switch 00, are open andthat, likewise, jthe contacts 390 of the rnechanical indicatorassociated with the oil switch 90 at the interconnection withanother'system are likewise open. Therefore, the only current suppliedto theboard under these circumstances is that supplied through-thecontacts of relays 30| and 302V under control of the interrupter I.Accordingly, while this condition remains the telltale symbols of theboard so equipped will intermittentlyflash Vand thus indicateV to thesupervisorthe representation of a no current condif tion. Y

- Y The supervisor changes the display condition of the board to agreewith changes occurring in the field as he is advised of them, or for thepurpose of setting up a proposed change which he believes necessary tothe proper maintenance of service. It will be assumed that thesupervisor has been advised from the eld that the generator has been cutinto service. The supervisor, accordingly operates his key Ki to itsalternate position and dials the digits 00 required to position thewipers 2 I 0 of the Strowger switch SS into connection with themechanical indicator 200 associated with the' oil switch 00.

The off-normal contacts 2H of the calling de.- Vice CD are closed duringall stages of operation of the calling device and during such periodpositive potential is supplied through the left contacts of keys KI andK to the conductors 2l2 and 2i3, respectively. The relay 2&5 accordinglybecomes energized and removes negative potential from the windings ofrelays 303 and 304 to unlock either of these relays if they happen to beenergized. at Vthis time. The applicationof positive potential toconductor Z Vcauses the relays 30l and 302Y to maintain the various lampsignals of the board lighted steadily during the operation of vthecalling device.

When the first digit 0 is dialled the impulse springs 2&0. are closedten times and accordingly ten impulses are transmitted from positivepotential, suppliedV through the left contacts of key Kl, through theimpulse springs 2 l0, through the right break contacts of key K, and thewinding of relay 20| to negative potential. The relay 20l follows theseimpulses and repeats positive impulses to the vertical magnet 205 by wayor" slow release relay 202 and the upper break contacts ofY relay 203.The stepping mechanism driven by the vertical magnet 205, accordingly,elevates the wiper 2| 0 opposite the tenth level of bank con-v tacts.VThe slow release relay 202 remains energized during transmission of theimpulse series and'at its contacts completes the circuit of relay 204.This latter relay at its contacts prepares an operating circuitfor relay2.03 and a holding circuit for itself, which, however, is not effectiveuntil relay Y202 `restores following the complete transmission of therstdigit. VThe relay 203, upon operating, transfers the operating circuitYof the switch from the .vertical magnet 205 to theV rotary magnet 206Vso that the second series of impulses transmitted by the calling deviceis transmitted to the rotary magnet which, through the medium ofV itsassociated mechanism, moves the wiper 2H) into engagement with the tenthcontact Yof the selected level. Y

The wiper 2I0 now being connected Ywithrthe mechanical indicator 200,associated with the oil switch symbol 00, is available for operation bythe supervisor. Thersupervisor now operates key K to its alternateposition, which substitutes the conductor extending to wiper 210 for theconductor extending toI the impulsing relay 20L It will be appreciatedtherefore that any subsequent operations of the calling device CD willcause positive potential impulses to be transmitted tol the wiper 2|0and to the winding of the indicator 200. The supervisor under thecircumstances assumed, transmits the required impulses to bring the camof the indicator into the proper position to close the contacts 000V inwhich position the drum of the indicator appropriately displays a colorrepresenting the closed position of theV represented switch. As a resultof the closure of contacts 300, tell-tale relay 305 becomes energizedandat one pair of its contacts closes the circuit of the lamp labeledGen. tell-tale, associated with the generator tell-tale symbol, thusindicating on the map that the generator is now connected tothe network.The relay 305 also applies positive potential to the line 306, and sinceall of the bus disconnect, line disconnect, and oil switches in the leftsection of the network are shown as being closed, this positivepotential is applied directly t the transformer bank No. 1 tell-talelamp, the line tell-tale #l lamp, the customers bank tell-tale lamp andto the winding of relay 30:4. This relay upon operating, since all ofthe mechanical indicators in the right hand section of the network areillustrated as being closed, excluding the one at the interconnection,supplies positive potential to the lamps included in this section of thenetwork. It will be seen, therefore, that, although the positivepotential is being intermittently applied through the interrupter to therelays 3M and 302, the operation of these relays will be without effectso long as current is steadily applied from other sources direct to thelamps.

The described operations would have been substantially the same had thesupervisor decided to close the contacts of the oil switch 93 at theinterconnection instead of employing current from the generator of thenetwork.

It will now be assumed that the supervisor has been advised that the oilswitch 63 has been tripped and that he desires to ascertain the effectof this change on the service. He accordingly operates key KI, transmitsthe digit 60, by operating the calling device as before, and in sodoing, connects the wiper 2|0 with the mechanical indicator 260associated with the oil switch symbol 30. He then operates key K and thecalling device :as required to open the contacts 360 of the mechanicalindicator, and to position such indicator as required to represent theopen condition of the represented oil switch 60 on the display map. Itshould be noted that, in the network shown, current is being suppliedfrom the generator source to the line conductor 307 by two paths,namely, by way of the line conductor 306 and conductor 308, comprisingthe path interrupted by the opening of the oil switch 63; and by thesecond path including the conductor 309 and a series of oil anddisconnect switches which are still closed. Therefore, the opening ofthe oil switch 60 is without effect except that there may be a deciencyof current supplied to the line conductor 301 under some circumstances.Therefore, in a system as shown, no change in the condition of thetell-tale symbols occurs at this time.

It will .now be assumed that the generator is disconnected from thesystem and that the supervisor, being so advised, selects and operatesthe mechanical indicator 200 to again open the contacts 300. Uponopening the contacts 300 the tell-tale relay 305 becomes deenergized andthe generator symbol lamp is accordingly extinguished. It will be seenthat when positive potential was applied to the line conductor 306 whenthe relay 305 was energized and with the consequent energizaticn of thesectionalizing relay 304, as previously described, positive potentialwas supplied from this relay over the right section of conductor 309 tothe line 301, back over line 308 and through the switching apparatus tothe line 306. Therefore, unless some special arrangements are providedthe deenergization of relay 305 will not result in the removal ofpositive potential from this loop circuit which now includes the windingof relay 304. It will be noted, however, that upon each operation of thecalling device to perform theV selection vof a mechanical indicator therelay 2I5 removes negative potential from the sectionalizing relays 303and 304 and in this manner insures their deenergization occurring eachtime a selection is made. These relays therefore can never remain lockedup in a loop circuit such as described.

If special provisions are not provided, the opening of right-handcontacts of relay 305, which at times may carry the load of a largenumber of lamps, will result in excessive arcing, resulting in damage tothese contacts. The same holds true as regards. the Various contacts ofthe mechanical indicators. This is especially true of more elaboratesystems than the one disclosed, as such systems involve the use of alarge number of lamps. The prevention of arcing of contacts included incircuits carrying loads too large to safely break, is taken care of bythe relays 30| and 302. These relays, as previously explained, aremaintained energized during the operation of the calling device CD andestablish individual circuits for the various lamps of the system duringthe time any of the chain circuits are being broken. In other words, therelays 30| and 302 may be termed load-shunting relays for the reasonthat they shunt the load from the contacts normally carrying it whilesuch contacts are being opened.

The selecting switch SS of Fig. 2, after each operation, is releasedconsequent to the restoration of key KI which closes a circuit for therelease magnet 201 by way of the off normal springs ON. These off normalsprings are automatically opened consequent to the restoration of theswitch wipers to their normal position.

What is claimed is:

l. In a signalling system, a plurality of signals, circuits for saidsignals including a circuit connected to all of said signals, signalcontrol contact sets interspersed throughout the length of said circuit,means for operating any set of said contacts to interrupt the circuitsof one or a plurality of said signals depending upon the contact setoperated, auxiliary circuits for all signals, and means for closing saidauxiliary circuits consequent to the actuation of said first means anduntil the desired set of said contact sets has been opened, eachauxiliary circuit including only suflicient current flow to operate onesignal.

2. In a signalling system, a plurality of contact sets connected inseries relation in a current feed conductor, a plurality of indicatingdevices energized over circuits including parts of said conductor andone or a plurality of the contact sets depending upon their point ofconnection with said conductor and the feed point or points of theconductor, means for operating any desired set of said plurality ofcontact sets to interrupt the circuits of those devices included in theinterrupted portion of the common circuit, auxiliary circuits for saidindicating devices, and means for completing said auxiliary circuits tomaintain such devices energized until after the interruption of theseries circuit, each auxiliary circuit carrying less current than saidconduct-ors.

3. In a signalling system, a multi-branch signalling circuit, contactsconnecting the branches in said circuit, signals included in saidbranches, means for energizing said signals over said bran'ches,shunting circuits for shunting said branches, each shunting circuitcarrying less current than the branch circuit which it shunts,

means for operating any of said contacts to disconnect one or aplurality of said branches from said circuit, and means operatedresponsive to the operation of said means for completing said shuntingcircuits to shunt said branches and to maintain said signals energizedduring the actuation of said first means. Y

4. In a signalling system, a signallingV circuit including aplurality'of branches, contacts connecting said branches in saidcircuit, signals connected to said branches, means for connecting apotential to said circuit to energize said signals over said branches,means for operating any of said contacts to disconnect one or aplurality of said branches from said circuit dependent upon Y thecontact'operated, and meansoperated re-v sponsive thereto for connectingsaid potential directly to each branch to maintain said signalsenergized and to thereby preventV the opening of anyV circuit' carryingas much current as the branches and thus prevent arcing at the operatedcontacts during the operation 'oi any of said contacts.

5. In a signalling system, a plurality of signals, Y

6. A signalling system as claimed in claim 5Y in which there is meansfor intermittently operating said relay While said impulse sender is notoperating to ash the lamps not otherwise lighted. Y

THOMAS U. WHITE.

